Mudslide forces road closure in Hillsborough

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A Hillsborough roadway was shut down for emergency repairs this week after heavy rains caused a landslide.

The slide in the 100 block of Woodridge Road took out a 30-foot section of roadway starting Saturday, according to Hillsborough police. Though no injuries or threatened homes were reported, the moving soil prompted the closure of the road to allow repairs to be made to the damaged area.

On Saturday afternoon, officials noticed a crack forming in the 100 block of Woodridge Road about 6 feet from the northbound shoulder, Hillsborough police Capt. Mark O’Connor said. The crack widened as saturated ground beneath the northbound lane began to turn to mud and slip downhill.

The slide exposed a 2-inch natural-gas supply line and a 6-inch water line, O’Connor said.

A National Weather Service forecaster said mudslides during this time of year aren’t surprising.

“Generally what is needed [for a landslide] is for the ground to become quite saturated,” said forecaster Duane Dykema, adding that the rainfall over the past two weeks has added extra weight to soil on steep slopes. Dykema said mudslides are rare during the first few months of winter, but more likely from January through March.

O’Connor said the cost to reconstruct the road could be as high as $50,000 to $70,000.

The heavy rains last weekend also caused a landslide on state Highway 84, closing the road between Skyline Boulevard and Portola Road in Woodside. That road reopened Saturday afternoon.